Problem 335Si AB CD intersect to K.Triangles KAE,KDH are similar so AE/DH= KA/KD,triangles KAD,KCB are similar so KA/KD=KC/KB and triangles KCF, KBF are similar so KC/KB=CG/BF then AE/DH=CG/BF.Then AE.BF=DH.CG.Is AHDE , CGBF concyclic so <FGB=FCB=<DAH=<DEH. Therefore E,H,E,F are concyclic.APOSTOLIS MANOLOUDIS 4 HIGH SHCOOL OF KORYDALLOS PIRAEUS GREECE